But when it comes to fitness, intermittent fasting feels a little more precarious. Is it really a good idea to send your body into a fasted state when you exercise nearly every day? It may not be for everyone, but some of the fittest people in the world swear by it. Here, six super-fit people explain why.

The science is of intermittent fasting is just so convincing.

"I started because I was closing in at about 15 hours of fasting without meaning to. I'm not a huge breakfast person, so I eat my first meal late in the morning anyway. I just realized I was doing this by default a couple of weeks ago, so I've gotten more serious about it since then. I'm trying it out because I know how good it is for me, but it's definitely been tough. So far I haven't seen any real difference—so maybe it isn't for me—but that could also be because I haven't gotten used to it yet. Only time will tell!" —Sarah Levey, founder of Y7 yoga

Intermittent fasting helped my digestion.

"I first got into intermittent fasting after reading and hearing the benefits on multiple blogs and podcasts as well. Once I understood the science and realized many people I looked up to in the industry were big fans of IF, I knew I had to experiment with it. So I started doing a 16/8 protocol and actually felt pretty good right away.

"I had to get used to working out on an empty stomach, so that wasn't the easiest thing in the world, but the biggest thing I've noticed with IF is how much better my digestion is. Giving my digestive system a break for 16 hours rather than 10 or so helps tremendously. Also, my cognitive function while fasting is like night and day compared to before. No brain fog, and so much more mental clarity have been the biggest benefits of doing IF. I also noticed I wasn't losing any muscle mass or strength in the gym. I think it's safe to say I'm a fan." —Drew Manning, trainer and TV show host

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Intermittent fasting makes my cravings go away.

"I tried intermittent fasting because I had read many good things about it and wanted to try it for myself and see how my body responded to it. At first I noticed a decrease in strength and performance, but that's quite common when bringing down size with a deficit in diet. I quickly found many benefits of fasting, though: I had a reduction in appetite and cravings. I felt satisfied and full after eating even when I was eating as much as usual. I don't go to bed hungry and I sleep better." —Heather Marr, New York-based trainer

Intermittent fasting gives me so much more energy.

"I've been doing it off and on for the past year, and I see it affecting my energy. I have much more energy in the mornings than I used to—I jump right out of bed. I haven't noticed anything too drastic in my practice, other than having more energy and feeling lighter without food in my belly to actually move and breath." —Caley Alyssa, RYT-900 and mbg class instructor

Intermittent fasting helps with joint inflammation.

"I first started fasting while attending the Rolf Institute when I heard it was beneficial for relieving joint inflammation and I wanted to test it myself. I do an intermittent fast on a daily basis, normally my intention is to eat no more than two meals per day generally between the hours of 11 a.m. and 6 p.m. I also think rules are meant to be broken, and the body can adapt to a wide variety of dietary approaches. Life is too short to confine yourself to a single box. But generally speaking, if I am doing a full-day or multiday fast, I will use that time to move more passively. Walking, yoga, and nature complement fasting well." —Aaron Alexander, founder of The Align Method

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Intermittent fasting helps decrease body fat in a manageable way.

"I’ve been doing IF for 18 months, and I started because I had read about the benefits and found that I was a good candidate for it. I wanted to change my body composition (decrease body fat) and find something manageable and maintainable that would give me consistent energy. I must break fast immediately after a workout to stay healthy, so I time it around my fast. Some days, if I have to work out early in the morning, I don't fast. I typically break fast, and by the time I get the carbs and protein from my first meal, I usually have a fantastically energized workout." —Rebecca Kennedy, holistic fitness trainer and founder of ACCESS